1. Field of the Invention
This invention relates to beaded dental floss, especially to coilable structures containing beaded dental-floss segments. More specifically, it pertains to apparatus and methods for forming spherical or spheroidal beads on the ends of dental floss segments by melting the ends of the floss or bonding beads thereto; and for installing the beaded floss segments into coilable structures, whereby a great number of segments can be stored in a small space, easily available to a user.
2. Description of the Prior Art
Dental floss having beads fixed to it for the purpose of easily handling the floss, especially by floss applicators, is known in the prior art.
U.S. Pat. No. 3,843,297 "Apparatus for Preparing Measured Lengths of Dental Floss" to Rene J. Espinosa teaches simultaneously cutting floss and forming "nubs" on the ends of "wax-coated, synthetic, unplasticized, vinyl-resin floss" by protecting portions of the floss from heat and exposing the rest of it to jets of burning gas. As shown in FIG. 6 of that patent, this tends to produce amorphous, roughly disk-shaped nubs on the ends of the floss segments.
U.S. Pat. No. 5,067,503 "Dental Apparatus for Flossing Teeth" to T. W. Stiles teaches molding the end portions of dental floss segments into a plastic card, part of which forms balls of plastic on the ends of the floss. The balls are attached to the rest of the card by fragile connections that can easily be broken, for removal of a floss segment therefrom.
U.S. Pat. No. 4,753,254 to the present inventors teaches pressing preformed beads onto a continuous strand of floss and fixing them with a bonding agent.
U.S. Pat. No. 2,702,555 "Dental Floss Holder" to Michael De Mar teaches fixing the ends of wax-coated dental floss into slots of a disposable floss applicator by melting the ends of the floss so that the wax in the floss flows into the slots to form a bond between the floss and the applicator. The resulting hubs at the ends of the floss segment are necessarily amorphous in order to function best for their intended purposes.
Other patents, known to the present applicants, that teach handling devices (e.g., beads, clamps, molded parts, knots, etc.) attached to dental floss, and associated apparatus for handling such floss, are listed as follows in chronologically-regressive order:
U.S. Pat. No. 5,174,414 to Norman Charatan
U.S. Pat. No. 5,159,943 to John J. Wilson
U.S. Pat. No. 4,986,289 to Charles E. McWhorter
U.S. Pat. No. 4,974,614 to Frank Selker
U.S. Pat. No. 4,898,196 to W. Jeter Eason
U.S. Pat. No. 4,162,687 to Leonard G. Lorch
U.S. Pat. No. 4,016,892 to Ingram S. Chodorow
U.S. Pat. No. 4,006,750 to Ingram S. Chodorow
U.S. Pat. No. 3,974,842 to Ingram S. Chodorow
U.S. Pat. No. 3,631,869 to Rene J. Espinosa
U.S. Pat. No. 3,474,799 to Vito P. Cappello
German Patent No. 1,095,460 to Gustav Frantz
U.S. Pat. No. 1,815,408 to James K. Jordan
None of the patents cited above teaches coilable structures that contain segments of dental floss having beaded ends, or how to make such structures; neither do they disclose methods and apparatus for forming spheroidal beads on the ends of floss segments by melting them in a way that avoids the formation of amorphous disks thereon.